Re: [cf-pointobsconvention] Draft 2



Don Murray wrote:
John-

John Caron wrote:

Re the Z axis, it would be nice to know for sure whether the Z axis
should be interpreted as 'surface'.  (Other possible surfaces
exist, and I suppose an abstract form of Z is also possible.  So if
we want determinism, we could either say "lack of characterization
always means surface" or "Z must be described, if only to say it is
'surface'.")

Yes, after thinking more about it, Im not so sure we should allow
data that doesnt have a z coordinate. A standard I think should be
allowed to insist on things like this.

Then what do you do with a hurricane track that does not have
an z associated with it?  Or a trajectory from ship point obs
that only have a latitude/longitude?  It seems like wasted
space to have to write out 0 for z for every point if you don't
have it and there are plenty of datasets out there without a
Z value.

Well, maybe you're right. I notice that CF currently doesnt require vertical coords. But as a visualizing client, how do you display? Wouldnt you prefer to insist on something?

Other opinions?



Don
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Don Murray                               UCAR Unidata Program
dmurray@xxxxxxxxxxxxxxxx                        P.O. Box 3000
(303) 497-8628                              Boulder, CO 80307
http://www.unidata.ucar.edu/staff/donm
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